Sutter Primary Treatment Facility

Prior to 1910, the City’s wastewater was discharged directly into the Tuolumne River at 9th Street. In 1919, the City purchased approximately 38 acres of land at the foot of Sutter Avenue and Martin Luther King (which is now known as the Sutter Wastewater Treatment Facility). An outfall line was installed rerouting flow to what was tantamount to a giant septic tank. The septic’s tank overflow was then discharged into the Tuolumne River at Sutter.

Screw Pumps draw wastewater up into the grit room for initial filtration

internal grooves in the screw pump grab water and push it up into the facility

the grit chamber provides the first level of filtration to the wastewater by passing it through a grate removing large debris and allowing inorganic solids to settle to the bottom for extraction

The wastewater is then directed to the 200 foot diameter, 2 million gallon clarifier where heavy solids sink and lighter contaminants float. Both are removed via a skimming arm

Over the years expansions took place: 1928 more acreage was purchased at Sutter, oxidation and percolation beds were constructed. In 1930 a 62ft clarifier was installed replacing the giant septic tank of 1919. In the years between 1937 and 1955 many improvements were constructed due to the stringency of the regulatory agencies. During the canning season, it was common practice to operate Sutter Facility differently than the off season, when most industry ceased production. This is a cycle that would continue for years.